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Caratterizzazione dei meccanismi di assorbimento e assimilazione dello S in piante di frumento Fe-carenti
No full textChanges in S assimilation pathway in response to S and Fe deficiency stress in wheat seedlings
No full textThe effect of excess sulfate supply on iron accumulation in three graminaceous plants at the early vegetative phase
No full textIn recent years it has been established a significant relationship between sulfur (S) and iron (Fe) nutrition. In particular, it has been demonstrated that S deprivation can hinder Fe acquisition in barley, maize and wheat. This can be explained by assuming that, in order to cope with low Fe availability in the soil, grasses have evolved a phytosiderophores (PS)-based Fe chelation system (Strategy II) and PS are synthesized from methionine, through a nicotianamine intermediate.On the other hand, it has been demonstrated that wheat plants exhibit a higher Fe accumulation when supplied with excess S concentration, this effect being especially beneficial under severely limited Fe supply.The goal of this study was to explore whether the higher ability to acquire Fe, induced by a higher S supply, might be a general response of graminaceous species.The response of durum wheat (Triticum durum L.), barley (Hordeum vulgare L.), and maize (Zea mays L.) to the excess of S availability (2.4 mM vs 1.2 mM which is considered as optimal) was studied as a function of Fe availability (limited and sufficient, 20 and 80 μM, respectively). At the end of the experimental period, which lasted 11 days, growth parameters (shoot and root fresh weight and chlorophyll content), total S and Fe concentrations, and PS release rate were compared among the three species. Furthermore, we evaluated plant sulfate uptake capability, by analysing the expression of genes coding for high affinity sulfate transporter (TdST1.1, HvST1.1 and ZmST1.1) in roots of each graminaceous plant.Our preliminary findings are largely consistent with the apparent divergence among the three species. In particular, an excess S supply may result in the improvement of Fe use efficiency in durum wheat plants, but not in both barley and maize.The use of higher S supply seems to be a promising approach, at least for wheat plants, which can both reduce agricultural demand for Fe fertilizers and improve the Fe use efficiency of plants
Changes in sulfur assimilation pathway induced by S and Fe deficiency in wheat seedlings
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Adattamenti di medio periodo nell’espressione genica di una latifoglia arbustiva mediterranea, Phillyrea latifolia L., esposta all’ozono. II. Isolamento di sequenza mediante cDNA-AFLP
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